- The Hexagonal Close Packed lattice is non-Bravais and like
the other common non-Bravais lattice, that of diamond, is common to many
interesting elements and compounds.
- HCP structures include one allotrope of solid Helium, and the metal
- Numerical studies on HCP are complicated by the two sublattice
nature, and it requires 4 Miller indices.
- The rich structure of HCP solid Helium makes the additional